US9653248B2 - X-ray tube - Google Patents
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- US9653248B2 US9653248B2 US14/582,782 US201414582782A US9653248B2 US 9653248 B2 US9653248 B2 US 9653248B2 US 201414582782 A US201414582782 A US 201414582782A US 9653248 B2 US9653248 B2 US 9653248B2
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- H01J35/00—X-ray tubes
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
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Definitions
- Embodiments described herein relate generally to an X-ray tube.
- X-ray tubes are applied to an X-ray image diagnosis, a nondestructive testing, etc.
- a stationary anode X-ray tube and a rotating-anode X-ray tube are present, and one of them is used in accordance with an intended use.
- the X-ray tubes each comprise an anode target, a cathode, and an envelope. A focus is formed in an anode target and emits X-rays when an electron beam collide the anode target.
- the cathode comprises a filament coil and an electron convergence cup.
- the filament coil can emit electrons which produce a tube current.
- a high tube voltage of several tens of kilovolts to hundreds of kilovolts is applied.
- the electron convergence cup can serve as an electron lens; that is, it can cause an electron beam traveling toward the anode target to converge.
- the rotating-anode X-ray tube is applied to a medical diagnosis.
- the following two focal spots are provided: a large focal spot which has great dimensions and in which large tube current can be input; and a small focal spot which has small dimensions and in which small tube current is input, but a resolution is high.
- three focal spots are provided in a certain X-ray tube. The dimensions of each of the focal spots depend on shapes of a filament coil and an electron convergence cup and a positional relationship between the filament coil and the electron convergence cup, and ordinarily, they are fixed.
- photographing conditions are determined after a spatial resolution and tube current (influencing a contrast and noise) are determined in accordance with an intended use in diagnosis, and either the large focal spot or the small focal spot is used properly.
- the dimensions of the focal spot are changed, they are hard to control such that they are set to desired dimensions.
- the variation of the length and width of the focal spot greatly differs from that of a bias voltage supplied to an electron convergence cup.
- a technique is proposed in which an electrode which controls the length of a focal spot and an electrode which controls the width of the focal spot are prepared, and the focal spot is controlled to have desired dimensions.
- FIG. 1 is a cross-sectional view showing an X-ray tube assembly of an embodiment
- FIG. 2 is a view which enlargedly shows a cathode of an example according to the embodiment; and which contains (a) a plan view, (b) a cross-sectional view, and (c) another cross-sectional view;
- FIG. 3 is a view containing schematic views which show a cathode and an anode target of the example as viewed in two directions perpendicular to a tube axis of the X-ray tube, and also show that where a bias voltage to be applied to an electron convergence cup is set to 0V which is equal to a filament voltage, an electron beam is emitted from a filament coil toward the anode target;
- FIG. 4 is a view containing schematic views which show the cathode and the anode target of the example as viewed in the two direction perpendicular to the tube axis of the X-ray tube, and also show that where the electron convergence cup is given a bias voltage which is negative with respect to the filament voltage, an electron beam is emitted from the filament coil toward the anode target;
- FIG. 5 is a view which shows as a graph, in the example, how dimensions of a focal spot vary in accordance with the bias voltage, where the filament voltage is 0V;
- FIG. 6 is a view which enlargedly shows a modification of the cathode of the embodiment; and which contains (a) a plan view, (b) a cross-sectional view, (c) another cross-sectional view, and (d) another cross-sectional view;
- FIG. 7 is a view which enlargedly shows another modification of the cathode of the embodiment; and which contains (a) a plan view, (b) a cross-sectional view, and (c) another cross-sectional view;
- FIG. 8 is a view which enlargedly shows a cathode and an electrode of a modification of the X-ray tube of the embodiment, and which contains (a) a plan view, (b) a cross-sectional view, and (c) another cross-sectional view;
- FIG. 9 is a perspective view which shows the other modification of the cathode of the embodiment, shows part of the cathode, and also shows a plate filament and a supporting member;
- FIG. 10 is a view which enlargedly shows a cathode of the above comparative example; and which contains and which contains (a) a plan view, (b) a cross-sectional view, and (c) another cross-sectional view;
- FIG. 11 is a view containing schematic views which show the cathode and an anode target of the comparative example as viewed in two directions perpendicular to a tube axis of an X-ray tube; and also show that where a bias voltage to be applied to an electron convergence cup is set to 0V which is equal to a filament voltage, an electron beam is emitted from a filament coil toward the anode target;
- FIG. 12 is a view containing schematic views which show the cathode and the anode target of the comparative example as viewed in the two directions perpendicular to the tube axis of the X-ray tube, and also show that where the electron convergence cup is given a bias voltage negative with respect to the filament voltage, an electron beam is emitted from the filament coil toward the anode target; and
- FIG. 13 is a view which shows as a graph how dimensions of a focal spot vary in accordance with the bias voltage in the comparative example, where the filament voltage is 0V.
- an X-ray tube comprising:
- anode target which emits X-rays upon incidence of an electron beam on the anode target
- a cathode including a filament and a convergence electrode which includes a groove portion in which the filament is provided, and which causes an electron beam to focus, the electron beam being emitted from the filament toward the anode target through an opening of the groove portion;
- a length direction of the groove portion is a direction along a major axis of the filament, and a width direction of the groove portion is a direction perpendicular to a depth direction and the length direction of the groove portion;
- the groove portion includes: a pair of first bottom surfaces which are located in the same plane as the filament and between which the filament is interposed in the width direction; and a pair of second bottom surfaces between which the filament and the pair of first bottom surfaces are interposed in the length direction and which are located closer to the opening than the pair of first bottom surfaces.
- the X-ray tube assembly is a rotating-anode X-ray tube assembly.
- the X-ray tube assembly comprises a rotating-anode X-ray tube 1 , a stator coil 2 serving as a coil which generates a magnetic field, a housing 3 which accommodates the X-ray tube and the stator coil, an insulating oil 4 serving as a coolant filled in the housing, and a controller 5 .
- the X-ray tube 1 comprises a cathode (cathode electron gun) 10 , a sliding bearing unit 20 , an anode target 60 and an envelope 70 .
- the sliding bearing unit 20 comprises a rotor 30 , a fixed shaft 40 serving as a fixed body, and a metallic lubricant not shown which serves as a lubricant, and uses sliding bearings.
- the rotor 30 is cylindrically formed, and one end portion of the rotor 30 is closed.
- the rotor 30 extends along the axis of rotation, which is a central axis of a rotating operation of the rotor.
- the above axis of rotation corresponds to a tube axis al of the X-ray tube 1 , and will be explained as the tube axis al.
- the rotor 30 can be rotated about the tube axis al.
- the rotor 30 includes a connection portion 31 located at the above one end portion.
- the rotor 30 is formed of iron (Fe), molybdenum (Mo) or the like.
- the fixed shaft 40 is cylindrically formed to have a smaller diameter than that of the rotor 30 . Also, the fixed shaft 40 is provided coaxial with the rotor 30 , and extends along the tube axis al. Furthermore, the fixed shaft 40 is fitted in the rotor 30 , and also formed of Fe, Mo or the like. One end portion of the fixed shaft 40 is exposed to the outside of the rotor 30 . In addition, the fixed shaft 40 supports the rotor 30 in such a manner as to permit the rotor 30 to be rotated.
- the metallic lubricant is filled in a gap between the rotor 30 and the fixed shaft 40 .
- the anode target 60 is located opposite to the other end portion of the fixed shaft 40 in a direction along the tube axis al.
- the anode target 60 includes an anode main body 61 and a target layer 62 provided on part of an outer surface of the anode body.
- the anode main body 61 is fixed to the rotor 30 by the connection portion 31 . Also, the anode main body 61 is discoid, and formed of Mo or the like; and can be rotated about the tube axis al.
- the target layer 62 is annular, and includes a target surface 62 S located opposite to the cathode 10 with a space between the target layer 62 and the cathode 10 in the direction along the tube axis al. In the anode target 60 , when an electron beam impinges on the target surface 62 S, it forms a focal spot, and X-rays are emitted from the focal spot.
- the anode target 60 is electrically connected to a terminal 91 via the fixed shaft 40 , the rotor 30 , etc.
- the cathode 10 includes one or more filament coils and an electron convergence cup 15 serving as a convergence electrode.
- the cathode 10 includes a filament coil 11 .
- the filament coil 11 is formed of material containing tungsten as a main ingredient.
- the filament coil 11 is formed to extend linearly.
- the filament coil 11 and the electron convergence cup 15 are electrically connected to terminals 81 , 82 and 83 .
- the electron convergence cup 15 includes one or more groove portions in which the filament coil or coils (electron emission source) are set.
- the electron convergence cup 15 includes a groove portion 16 in which the filament coil 11 is set.
- the filament coil 11 is located apart from an inner surface (bottom surface) of the groove portion 16 .
- the filament coil 11 is supplied with a current (filament current). As a result, the filament coil 11 emits electrons (thermal electrons).
- the anode target 60 is given a relatively positive voltage by the terminal 91 through the fixed shaft 40 , the rotor 30 , etc.
- the filament coil 11 and the electron convergence cup 15 are given a relatively negative voltage by the terminals 81 to 83 .
- an X-ray tube voltage (hereinafter referred to as a tube voltage) is applied, as a result of which the electrons emitted from the filament coil 11 are accelerated to be incident as an electron beam onto the target surface 62 S.
- the electron convergence cup 15 makes converge the electron beam, which is emitted from the filament coil 11 toward the anode target 60 through an opening 16 a of the groove portion 16 .
- the envelope 70 is cylindrically formed.
- the envelope 70 is formed of a combination of, e.g., metal and insulating material such as glass or ceramic.
- the diameter of part of the envelope 70 which is located opposite to the anode target 60 , is greater than that of part of the envelope 70 , which is located opposite to the rotor 30 .
- the envelope 70 includes an opening 71 .
- the opening 71 is made adhered to one end portion of the fixed shaft 40 to maintain a vacuum-tight state of the envelope 70 .
- the envelope 70 is fixed to the fixed shaft 40 .
- To an inner wall of the envelope 70 the cathode 10 is attached.
- the envelope 70 is vacuum-tightly sealed, and accommodates the cathode 10 , the sliding bearing unit 20 , the anode target 60 , etc.
- the inside of the envelope 70 is kept in a vacuum state.
- the stator coil 2 is provided such that in a position opposite to a side surface of the rotor 30 , the stator coil 2 surrounds an outer peripheral part of the envelope 70 . Also, the stator coil 2 is annular; and it is electrically connected to a current supplying terminal (not shown), and is driven therewith.
- the housing 3 includes an X-ray transmission window 3 a which causes X-rays to be transmitted therethrough.
- the X-ray tube 1 and the stator coil 2 are provided, and the insulating oil 4 is filled.
- a controller 5 is electrically connected to the cathode 10 via the terminals 81 , 82 and 83 . Also, the controller 5 can drive and control the filament coil 11 .
- the stator coil 2 is driven with terminals 92 and 93 to generate a magnetic field.
- the stator coil 2 generates a rotation torque to be given to the rotor 30 .
- the rotor is rotated, and the anode target 60 is thus also rotated.
- the controller 5 gives a filament current for driving the filament coil 11 , through the terminals 81 to 83 , and the filament coil 11 and the electron convergence cup 15 are given a relatively negative high voltage (common voltage).
- the negative high voltage is, e.g., approximately minus several tens of kilovolts to minus 150 kilovolts.
- a ⁇ 5 Kv to 0V of bias voltage (superimposed voltage with respect to a filament voltage) is applied.
- a relatively positive voltage is applied through the terminal 91 .
- tube current an X-ray tube current (hereinafter referred to as tube current) flows from the cathode 10 to a focal spot on the target surface 62 S.
- the target layer 62 emits X-rays upon incidence of an electron beam on the target layer 62 , and the X-rays emitted from a focal spot are output to the outside of the housing 3 through the X-ray transmission window 3 a .
- the focal spot is formed to have a length corresponding to a major axis of the filament coil 11 and a width corresponding to a minor axis of the filament coil 11 .
- the X-ray tube assemblies of the embodiment and the comparative example are formed in the same manner, except for the groove portions of the electron convergence cup 15 .
- an opening 16 a of a groove portion 16 is formed in a rectangle having sides along in a first direction da and sides along a second direction db.
- the first direction da is a length direction of the groove portion 16 and also a direction along the major axis of a filament coil 11 .
- the second direction db is a width direction of the groove portion 16 , and also a direction perpendicular a depth direction and length direction of the groove portion.
- the depth direction of the groove portion 16 is a third direction dc.
- the groove portion 16 includes a pair of first bottom surfaces S 1 , a pair of second bottom surfaces S 2 and a third bottom surface S 3 .
- the opening 16 a , the pair of first bottom surfaces S 1 , the pair of second bottom surfaces S 2 and the third bottom surface S 3 are parallel to each other.
- the third bottom surface S 3 is located opposite to the filament coil 11 in the third direction dc.
- the third bottom surface S 3 is formed in a rectangle having long sides along the first direction da and short sides along the second direction db. In the first direction da and the second direction db, the third bottom surface S 3 are formed to have greater dimensions than those of the filament coil 11 .
- the filament coil 11 is located in the same plane as the pair of first bottom surfaces S 1 .
- the third bottom surface S 3 is interposed between the pair of first bottom surfaces S 1 in the second direction db.
- the pair of first bottom surfaces S 1 are located closer to the opening 16 a than the third bottom surface S 3 .
- the third bottom surface S 3 and the pair of first bottom surfaces S 1 are interposed between the pair of second bottom surfaces S 2 in the first direction da.
- the pair of second bottom surfaces S 2 are located closer to the opening 16 a than the pair of first bottom surfaces S 1 .
- the pair of second bottom surfaces S 2 are located opposite to end portions of the filament coil 11 in the second direction db.
- the opening 16 a of the groove portion 16 is formed in the shape of a rectangle having sides along the first direction da and sides along the second direction db.
- the groove portion 16 includes a third bottom surface S 3 and first bottom surface S 1 .
- the third bottom surface S 3 is opposed to a filament coil 11 in the third direction dc.
- the third bottom surface S 3 is formed in the shape of a rectangle having long sides along the first direction da and short sides along the second direction db. In the first direction da and the second direction db, the third bottom surface S 3 is formed to have greater dimensions than the filament coil 11 .
- the filament coil 11 is located in the same plane as the first bottom surface S 1 .
- the first bottom surface S 1 is formed in the shape of a frame, and surrounds the third bottom surface S 3 .
- the first bottom surface S 1 is located closer to the opening 16 a than the third bottom surface S 3 .
- the inventors of the present invention performed a computer simulation in which X-rays are emitted using the X-ray tube assembly of the example and also a computer simulation in which X rays are emitted using the X-ray tube assembly of the comparative example.
- a bias voltage to be applied to the electron convergence cup 15 was adjusted.
- the focal spot formed on the target surface 62 S is a single focal spot. Also, the simulations were performed under the same conditions.
- the filament coil 11 and the electron convergence cup 15 were given the common negative high voltage, and a bias voltage to be applied to the electron convergence cup 15 was set to 0V, to thereby form a large focal spot F 1 on the target surface 62 S. Electrons were emitted from an entire region of the filament coil 11 toward the target surface 62 S. An electron beam is focused by the action of an electric field generated by the groove portion 16 of the electron convergence cup 15 .
- the length and width of a formed large focal spot (effective focal spot) F 1 will be denoted by L and W, respectively.
- the filament coil 11 and the electron convergence cup 15 were given the common negative high voltage, and further the electron convergence cup 15 was given a bias voltage which is negative with respect to a filament voltage, to thereby form a small focal spot F 2 on the target surface 62 S. Electrons were emitted from a central portion of the filament coil 11 toward the target surface 62 S. At the end portions of the filament coil 11 , the action of the electric field was strong, as compared with that at the central portion thereof, and the number of electrons emitted from the end portions of the filament coil 11 was reduced. The electron beam is focused by the action of the electric field generated by the groove portion 16 of the electron convergence cup 15 .
- the width of a formed small focal spot (effective focal spot) F 2 was 0.5 W. Furthermore, as described above, since the number of electrons emitted from the end portions of the filament coil 11 was reduced, the length of the small focal spot (effective focal spot) F 2 was 0.5 L. It should be noted that the variation of the length of the small focal spot F 2 can be handled by changing the shapes of steps of the groove portion 16 . It therefore suffices that the shapes of the steps of the groove portion 16 are designed as appropriate in accordance with the purpose of use of the X-ray tube 1 .
- the bias voltage applied to the electron convergence cup 15 was continuously changed, and the dimensions of the focal spot were measured.
- the length of the focal spot varies in accordance with the width of the focal spot. It is found that the length and width of the focal spot can be simultaneously changed to the same direction (increase or decrease) by changing the bias voltage applied to the electron convergence cup 15 . This can be true of at least the case where the length of the small focal spot F 2 falls within the range of 0.5 L to 0.8 L, and the width of the small focal spot F 2 falls within the range of 0.5 W to 0.8 W.
- the filament coil 11 and the electron convergence cup 15 were given the common negative high voltage, and where a bias voltage applied to the electron convergence cup 15 was set to 0V, a large focal spot F 1 was formed on the target surface 62 S.
- the large focal spot (effective focal spot) F 1 was formed in the same manner as in the example, and the length and width of the large focal spot F 1 will be denoted by L and W, respectively.
- the filament coil 11 and the electron convergence cup 15 were given the common negative high voltage, and the electron convergence cup 15 was further given a negative bias voltage, as a result of which a small focal spot F 2 was formed on the target surface 62 S. Electrons were emitted from the entire region of the filament coil 11 toward the target surface 62 S. The number of electrons emitted from end portions of the filament coil 11 was not reduced.
- the width of the formed small focal spot (effective focal spot) F 2 was 0.5 W. Also, as described above, since the number of electrons emitted from the end portions of the filament coil 11 was not reduced, the length of the small focal spot (effective focal spot) F 2 was 0.85 L.
- the bias voltage applied to the electron convergence cup 15 was continuously changed, and the dimensions of the focal spot were measured.
- the width of the focal spot varies in accordance with the variation of the bias voltage, the length of the focal spot is hardly changed.
- the X-ray tube 1 comprises the anode target 60 which emits X rays upon incidence of an electron beam on the anode target 60 , the cathode 10 which includes the electron convergence cup 15 , and the envelope 70 which accommodates the anode target 60 and the cathode 10 .
- the electron convergence cup 15 includes the groove portion 16 in which the filament coil 11 is provided.
- the groove portion 16 includes the pair of first bottom surfaces S 1 , the pair of second bottom surfaces S 2 and the third bottom surface S 3 . Of those surfaces, the third bottom surface S 3 is located at the deepest position, and the second bottom surfaces S 2 are in the shallowest positions.
- the groove portion 16 includes the third bottom surface S 3 .
- a hole which permits legs of the end portions of the filament coil 11 to pass through the hole is formed to penetrate the electron convergence cup 15 .
- processing cutting processing
- heat emitted from the filament coil 11 is reflected from the third bottom surface S 3 toward the filament coil 11 , and the temperature of the filament coil 11 is thus easily increased. Thereby, the number of electrons emitted from the filament coil 11 can be efficiently increased.
- the cathode 10 may include a plurality of filament coils.
- the electron convergence cup 15 may also include a plurality of groove portions which correspond in number to the filament cols.
- the cathode 10 includes the filament coil 11 serving as a first filament coil which emits electrons and a filament coil 12 serving as a second filament coil which emits electrons.
- the electron convergence cup 15 includes the groove portion 16 serving as a first groove portion in which the filament coil 11 is provided and a groove portion 17 serving as a second groove portion in which the filament coil 12 is provided.
- the electron convergence cup 15 causes an electron beam emitted from the filament coil 11 toward the anode target 60 through the opening 16 a of the groove portion 16 to focus, and also causes an electron beam emitted from the filament coil 12 toward the anode target 60 through an opening 17 a of the groove portion 17 to focus.
- the groove portion 16 includes the pair of first bottom surfaces S 1 , the pair of second bottom surfaces S 2 and the third bottom surface S 3 .
- the groove portion 17 includes a pair of first bottom surfaces S 4 , a pair of second bottom surfaces S 5 and a third bottom surface S 6 .
- the third bottom surface S 6 is located opposite to the filament coil 12 in a depth direction of the groove portion 17 .
- the filament coil 12 is located in the same plane as the pair of first bottom surfaces S 4 .
- the third bottom surface S 6 is interposed in a width direction of the groove portion 17 ; and also the pair of first bottom surfaces S 4 are located closer to the opening 17 a of the groove portion 17 than the third bottom surface S 6 .
- the pair of second bottom surfaces S 5 , the third bottom surface S 6 and the pair of first bottom surfaces S 4 are interposed in a length direction of the groove portion 17 ; and also the pair of second bottom surfaces S 5 are located closer to the opening 17 a of the groove portion 17 than the pair of first bottom surfaces S 4 .
- a plurality of filament coils are included in the cathode 10 , they may be of the same kind or of different kinds. If different kinds of filaments coils are provided, it is possible to select any of a plurality of focal spots having different dimensions. If the same kind of filament coils are provided, it is possible to increase the lives of the filament coils by alternately using them.
- the groove portions 16 and 17 may be formed without including the third bottom surfaces S 3 and S 6 .
- the groove portion 16 is formed without including the third bottom surface S 3 .
- This can obtain the same advantages as the embodiment, except for an effect of heat reflection by the third bottom surface S 3 , in the case where of the bottom surfaces of the groove portion 16 , the third bottom surface S 3 has substantially no effect on the electron beam convergence.
- a filament assembly is assembled from the filament coil 11 and an insulating member not shown which holds the filament coil 11 , it can be attached to the electron convergence cup 15 .
- attachment of the filament assembly can be achieved by inserting the filament coil 11 from a reverse surface side (opposite side of the opening 16 a ) of the electron convergence cup 15 into the electron convergence cup 15 , and fixing the insulating member to the reverse surface side of the electron convergence cup 15 .
- the groove portions 16 and 17 are formed without including the third bottom surfaces S 3 and S 6 , the cathode 10 can be more easily assembled than in the embodiment.
- the X-ray tube 1 may further comprise a pair of electrodes 50 which are given a voltage which is negative with respect to the voltage applied to the filament coil 11 .
- the pair of electrodes 50 are provided between the anode target 60 and the cathode 10 .
- the pair of electrodes 50 are located opposite to each other in the length direction (the first direction da and the direction along the major axis of the filament coil 11 ) in such a manner as to surround the path of an electron beam.
- the pair of electrodes 50 are fixed to the electron convergence cup 15 , with an insulating material 51 interposed between the electron convergence cup 15 and the pair of electrodes 50 .
- the pair of electrodes 50 can be given a voltage which is the same as the voltage applied to the electron convergence cup 15 .
- the pair of electrodes 50 can be given a voltage which is negative with respect to the voltage to be applied to the electron convergence cup 15 .
- the pair of electrodes 50 are given a voltage to be applied to the filament coil 11 , and further given a bias voltage (superimposed voltage) which is negative with respect to the filament voltage.
- An electron beam is caused to focus by the action of an electric field generated by the groove portion 16 of the electron convergence cup 15 and that of an electric field generated by the pair of electrodes 50 . Due to addition of the action of the electric field by the pair of electrodes 50 , the length of a focal spot can be further shortened, while a density distribution of electrons in the focal spot is kept uniformized.
- the filament which serves as the electron emission source, is not limited to the filament coil; that is, various kinds of filaments can be applied.
- the cathode 10 may include a plate filament 13 instead of the filament coil 11 .
- the plate filament 13 is a filament formed in the shape of a plate including a flat filament upper surface (electron emission surface) 13 a and a reverse surface.
- the filament upper surface 13 a is exposed to a region close to the opening 16 a.
- the filament upper surface 13 a is a flat surface along the first direction da and the second direction db. Also, the filament upper surface 13 a is parallel to the pair of first bottom surfaces S 1 and the pair of second bottom surfaces S 2 .
- the plate filament 13 is located in space between the third bottom surface S 3 and the pair of second bottom surfaces S 2 in the third direction dc.
- the plate filament 13 has a major axis in the first direction da, and extends in the first direction da.
- slits SL are formed to prevent the plate filament 13 from being divided. Thereby, a temperature distribution of the plate filament 13 can be uniformized.
- Plate-like supporting members 13 s are connected to both end portions of the plate filament 13 in the first direction da.
- the supporting members 13 s support the plate filament 13 , and also fix the plate filament 13 in position.
- the supporting members 13 s are formed of conductive material, and also function as conductive members which apply voltage and current to the plate filament 13 .
- the supporting members 13 s and the plate filament 13 can be formed as a single body.
- the X-ray tube of the present invention can be applied not only to the above-mentioned X-ray tubes; but it can be variously modified and can also be applied to various kinds of X-ray tubes.
- the X-ray tube of the present invention can be applied to a stationary anode X-ray tube.
Abstract
Description
-
- When a bias voltage is not applied to the
electron convergence cup 15, a large focal spot F1 can be formed. Since the tube current can be increased, photographing can be performed with X rays having a greater intensity. - The number of electrons emitted from the end portions of the
filament coil 11 can be reduced to form a small focal spot F2, by adjusting the bias voltage to be applied to theelectron convergence cup 15. The length and width of the focal spot can be changed to the same extent. It is possible to perform photographing with a high resolution. At this time, the dimensions of the focal spot and the tube current can be simultaneously adjusted by adjusting the bias voltage, and an optimal photographing can be carried out.
- When a bias voltage is not applied to the
Claims (10)
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JP2012148335 | 2012-07-02 | ||
JP2012-148335 | 2012-07-02 | ||
PCT/JP2013/067852 WO2014007167A1 (en) | 2012-07-02 | 2013-06-28 | X-ray tube |
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PCT/JP2013/067852 Continuation WO2014007167A1 (en) | 2012-07-02 | 2013-06-28 | X-ray tube |
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US20150117617A1 US20150117617A1 (en) | 2015-04-30 |
US9653248B2 true US9653248B2 (en) | 2017-05-16 |
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US14/582,782 Active 2033-12-29 US9653248B2 (en) | 2012-07-02 | 2014-12-24 | X-ray tube |
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US (1) | US9653248B2 (en) |
EP (1) | EP2869327B1 (en) |
JP (1) | JP6223973B2 (en) |
CN (1) | CN104428865B (en) |
WO (1) | WO2014007167A1 (en) |
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US20170092456A1 (en) * | 2015-09-28 | 2017-03-30 | General Electric Company | Flexible flat emitter for x-ray tubes |
US20170287670A1 (en) * | 2016-04-01 | 2017-10-05 | Toshiba Electron Tubes & Devices Co., Ltd. | Emitter and x-ray tube |
US20180350549A1 (en) * | 2017-06-05 | 2018-12-06 | General Electric Company | Flat Emitters With Stress Compensation Features |
US20230197397A1 (en) * | 2021-12-21 | 2023-06-22 | GE Precision Healthcare LLC | X-ray tube cathode focusing element |
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US9779907B2 (en) * | 2015-01-28 | 2017-10-03 | Varex Imaging Corporation | X-ray tube having a dual grid and dual filament cathode |
WO2017073109A1 (en) * | 2015-10-28 | 2017-05-04 | 東芝電子管デバイス株式会社 | Rotating anode x-ray tube |
JP6638966B2 (en) * | 2016-06-20 | 2020-02-05 | キヤノン電子管デバイス株式会社 | X-ray tube |
US10373792B2 (en) * | 2016-06-28 | 2019-08-06 | General Electric Company | Cathode assembly for use in X-ray generation |
JP6816921B2 (en) * | 2016-10-03 | 2021-01-20 | キヤノン電子管デバイス株式会社 | X-ray tube |
US10818466B1 (en) * | 2019-05-01 | 2020-10-27 | GE Precision Healthcare LLC | X-ray tube and cathode cup with deposition shield |
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US20170092456A1 (en) * | 2015-09-28 | 2017-03-30 | General Electric Company | Flexible flat emitter for x-ray tubes |
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US20230197397A1 (en) * | 2021-12-21 | 2023-06-22 | GE Precision Healthcare LLC | X-ray tube cathode focusing element |
Also Published As
Publication number | Publication date |
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CN104428865B (en) | 2017-04-26 |
CN104428865A (en) | 2015-03-18 |
WO2014007167A1 (en) | 2014-01-09 |
EP2869327A1 (en) | 2015-05-06 |
US20150117617A1 (en) | 2015-04-30 |
EP2869327B1 (en) | 2023-10-25 |
JP6223973B2 (en) | 2017-11-01 |
JPWO2014007167A1 (en) | 2016-06-02 |
EP2869327A4 (en) | 2016-03-09 |
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